镉对小鼠睾丸细胞DNA损伤及锌保护作用研究

目的 建立亚慢性镉中毒动物模型并研究镉对雄性小鼠睾丸细胞DNA损伤，及锌对亚慢性镉中毒的保护作用。方法 以不同剂量的氯化镉(0．4，0．8，1．6mg／kg)每天在ICR小鼠背部行皮下注射，连续7周。锌保护组在皮下注射1．6mg／kg体重氯化镉溶液的同时给予350μg／ml硫酸锌水溶液喂饲7周。动物处死后，取一侧睾丸做单细胞凝胶电泳实验以观察睾丸细胞DNA损伤水平，另一侧睾丸作病理切片镜下观察其组织形态变化。结果 各组血、肝镉浓度随染毒剂量增加而增加，呈现明显相关关系。病理损伤随剂量的增加而明显加重。睾丸细胞DNA损伤水平和损伤程度与染毒剂量呈现剂量—反应关系。高剂量染毒组部分睾丸细胞彗星图像呈凋亡改变。结论 亚慢性镉染毒可造成雄性小鼠睾丸组织的病理损伤，也可以引起睾丸细胞DNA损伤，且呈剂量—反应关系。锌对镉的亚慢性毒作用具有一定的保护作用，但锌似无驱镉作用，也不能降低镉中毒引起的睾丸细胞DNA损伤。

Effect of subchronic caium exposure on DNA damage of testicle cells in mice and protective effect of zinc sulfate

ObjectiveTo establish the model of subchronic cadmium ex posure in mice,and study the effect of DNA damage of testicle cells at the same time,the protective effect of zinc sulfate (ZnSO 4) on subchronic exposure were also studied.MethodsFour groups of ICR mice were injected everyday wi th cadmium chloride by the different dose (0.4,0.8,1.6?mg/kg,) for 7 weeks.The group of 1.6?mg/kg also fed with ZnSO 4.When the exposure was finished, the concentration of cadmium in blood and liver were determined by atomic absorp tion spectrophotometer,and the morphological changes of testes were also observe d.The single cell gel electrophoresis(SCGE,Comet assay)technique was used to det ect the DNA damage of testicle cells. ResultsCadmium concentration in blood and liver in the e xposure groups increased along with the exposure dose of cadmium contents increa sed.The results of coefficient viscera of testes,the pathological changes,and th e DNA damage levels of testicle cells showed that cadmium could damage the teste s to a different degree in a good dose-effect relationship manner.If ZnSO 4 was u sed in the group of cadmium chloride(1.6?mg/kg)exposure,the pathological damage s of testes were decreased even near to the levels of control group,but at the s ame time,the DNA damage of testicle cells were not improved by Zinc. ConclusionThe model of subchronic cadmium-exposed mice was set up successfully.Cadmium exposure may induce the DNA damage of testes cel ls,zinc sulfate could improve the subchronic pathological damage in testes indu ced by cadmium in a certain degree,but the protective effect of zinc was not sho wed in DNA damage level.